Fangrui Product Details Essential Tool For Seasonal Checks: This Circulation Pump Rotation Tester Is Invaluable At The Start Of The Heating Season, Allowing Users To Verify The Operation Of Circulation Pumps And Identify Any Potential Blockages After Extended Periods Of Inactivity. Versatile Functionality: In Addition To Testing Circulation Pumps, This Device Can Also Check The Operation Of Oil Burner Solenoid Valves, Making It A Multi-functional Tool For Various Heating Applications. Clear Indicator System: The Built-in Indicator Effectively Displays The Magnetic Field And Rotation Direction Of Most Circulation Pumps, Providing Immediate Image On Pump Performance For Quick Diagnostics. User-friendly Design: Designed For Convenience, The Redwhite Screw Rotates In Sync With The Pump, Allowing Users To Visually Confirm The Direction Of Pump Rotation Easily. Compact And Portable: Small Enough To Fit On A Key-ring, This Tester Is An Essential Item That Every Plumber Or Heating Contractor Should Have, Enabling Quick Checks Of Pu Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.